U.S. Pat. No. 4,688,987 to Ericson et al discloses a centrifugal pump having a split impeller which is mounted directly to an existing drive shaft. The inner surfaces of the hub portions of the split impeller are knurled or otherwise provided with ridges as to bite or lock the hub against the drive shaft when the two portions of the impeller are clutched together.
This prior centrifugal pump is particularly adapted for use in the engine compartment or hull of a marine vessel wherein the impeller is attached for rotation with the drive shaft, such as a propeller drive shaft, such as a propeller drive shaft, and wherein the pump housing is mounted so as to be in a surrounding and spaced relationship to the impeller blades and drive shaft. The impeller is freely rotatable in order to pump fumes, solids, or fluids through annular intake openings in the pump housing and deliver the same through an outlet formed in the pump housing.
U.S. Pat. No. 5,051,071 to Haentjens discloses a split impeller centrifugal pump for mounting on an existing drive shaft. The pump has opposed annular inlets. The pump does not contain vanes but grooves and air ducts.
It is an object of this invention to provide a self priming centrifugal pumping apparatus which couples to a drive shaft in an environment wherein liquids, gases, or solids may be encountered and wherein the pump is structured so that the impeller is not journaled or directly mounted to the pump housing. In this manner, no heat is generated during the rotation of the impeller by friction between the impeller and the housing as is the case in a pump which the impeller is directly carried by the pump housing.
It is also an object of the present invention to provide a centrifugal pump apparatus which is coupled between the engine and the drive shaft to provide a pumping apparatus which does not require the lubrication and maintenance associated with conventional centrifugal pumps.
It is another object of the invention to provide an improved self priming pump for removing liquid from a vessel or container that is operated from nearby or remote areas.